The field of Digital Pathology has been recently experiencing an accelerating growth, and its associated technology is moving toward widespread adoption. The resulting efficiencies include reduction in cost, time, and management overhead associated with traditional Pathology services. The reduction in distribution of glass slides between in-house physicians and external physicians performing second opinions or referrals is central to the increase in efficiency. Additionally, other associated activities, including searching for slides for publications and presentations are made more efficient when the digital form's acquisition and distribution are performed digitally rather than physically. Logistical efficiencies in the workflow of slide production, digitization and immediate archival can relieve the already overburdened health care facilities and provide a multitude of additional capacity and services as well. Finally, as there is no single physical piece of media to be viewed, an individual image or study can be accessed simultaneously by multiple local or remote users.
At the time of this filing, there are five characteristic Digital Pathology scenarios that serve to clearly define how Digital Pathology is being deployed and planned. These five scenarios are: Stand Alone Organizations, Expanding Primary Opinion Networks, Point-to-Point Second Opinion Networks, Peer Networks, and Cloud Networks. The Stand Alone scenario is primarily concerned with the intra-organization efficiencies of digitizing slides and archiving slides for in house pathology services. In the Expanding scenario, the health facility is looking to augment or outsource their own pathology services to a second organization, facility or expert center offering external pathology services, possibly obviating the requirement for intra-organizational pathology services, and leveraging the Digital Pathology System of the second organization. The Point-to-Point scenario is a dedicated second opinion or subspecialty service provided by a second organization to a first organization, where the first organization still maintains its own Digital Pathology System. The Peer-base scenario defines two or more organizations that leverage each of their Digital Pathology services to provide both combined primary and direct secondary pathology services to both organizations. The Cloud Network scenario is more of a speculative scenario where global pathology services can be leveraged by an organization in order to leverage efficiencies of scale without a direct linear relationship of that scaling to cost.
Stand Alone Organizations
For a digital pathology solution inside of an organization (Inside an organization does not denote network topology as much as all personnel accessing the digital pathology system have network credentials and can access the system either directly or through existing hospital security infrastructure) digital pathology applications (including triage, reports generation and primary diagnostic viewing) can be achieved through a direct connection to the deployed metadata & imaging services (see Architecture 1). In this case, because the pathologist is directly related to the organization requesting the diagnosis, the pathologist would have access to all of the patient data available via the metadata services, so no summarization, reduction or filtering of metadata is required. Also, because of the low utilization (an image is likely to be triaged, diagnosed and reported only once), caching or generation of preview images (a low- or mid-resolution image to be used during the triage, assignment and reporting processes) for some stages of the workflow are not necessary.
Expanding Primary Opinion Networks
In many remote areas of both the United States and the rest of the world, Pathology Service is still provided by travelling pathologists who cover a group of associated or independent hospitals by travelling between them. In this instance, the highest priced resource in the network is being moved from point-to-point through the network, with significant portions of their time being consumed by travel. Alternatives are to ship the slides to be read to a hospital with pathology services. The downside of this method is that slides are often lost or broken in the two-way transit from source to pathology resource, and this does not provide for rapid diagnostic ability. Extending the bounds of a pathology department's primary diagnostic ability to include remote hospitals that are either under-staffed or do not have the proper specialties is the next major arena for networked pathology.
Image previews first come into play in the case where remote digitizers are deployed to affiliated hospitals where no primary pathology service exists, the primary organization is performing the primary diagnostic service, expanding the effective footprint for the primary organization. In this case, all of the metadata and patient details are entered (or imported) into the primary organization's metadata services, as this is the primary patient record for the pathology system. The images, which exist at the remote location, will have a preview image created (which will be cached at the primary organization) for the triage, assignment and reporting processes. Only during the actual primary diagnosis of the image will the full resolution images be accessed from the remote site.
Point-to-Point Second Opinion Networks
The easy first step towards a networked telepathology solution is the addition of a dependent second organization to provide second opinions on cases. The metadata and image data are retrieved in the same manner as with a primary organization's diagnosis, and the nature of the dependent second organization (a dependent secondary organization does not require any hardware or software to enable their diagnostic abilities, thus they do not have a hardware of software footprint to which info can be cached) does not require or provide an efficient opportunity to cache either a preview image or metadata that would represent a lower-cost (from a network consumption perspective) solution than fetching the data directly from the primary organization's system as needed. This methodology is equivalent to providing limited network credentials and/or providing point-to-point secure network access to any person or organization providing second opinions to the primary institution.
Once the scope of a pathology solution expands beyond the bounds of a single organization with a single physical footprint, some level of data and/or image caching can be effective in reducing server load and bandwidth required to deploy an effective digital pathology system.
Peer Networks
A Peer Network scenario differs from the Primary/Dependent scenario by the fact that both organizations have a networked digital pathology system, and those systems can exchange studies. Cached metadata become useful and, coupled with a preview image, form a package which can be forwarded to a stand-alone peer system at a second organization. The first architecture requiring the forwarding of packages is the peer organization model, where two organizations (each is an independent organization with their own digital pathology solution) can be directly connected to one another and exchange studies (a package consisting of preview images, the study-specific metadata and security tokens for accessing the full image) for second opinions or consultation. Directly connecting the two organizations involves establishing network links and exchanging security certificates, and allows for the trusted exchange of information. Once connected, studies are directly assigned from one organization to another, and the queue of studies to be processed is the combination of all studies from the primary organization and all studies which have been referred to it by peer organization(s).
Cloud Networks
The evolution of networked pathology services is the cloud model. In the cloud model, studies are not directly assigned to an organization, but instead are made available to a specified group of recipients for second opinion. In the cloud model, the package is similarly made up of preview images, study-specific metadata and, instead of security tokens, a list of authorized recipients. The recipients may represent individual doctors, well known groups of doctors or other organizations. When a member of the recipient list views and accepts the study, that recipient has claimed the study and it is no longer available to the other recipients (first come, first served). This provides the quickest possible diagnosis for the study from the list of acceptable organizations and individuals, and will lead to the creation of ‘expert groups’.